The type of body you're looking for and the sort of flying your character will be doing have a significant bearing on what sort of wings they'll need. The "ideal" bodytype would perhaps be harpy-like, without unaerodynamic things like clothes or extra limbs (which would also be dead-weight when flying). Deep chest with massive muscles. Much more lightweight bones. Probably a pointier head. Much less weight and muscle in the legs and buttocks (again, deadweight, no good for flying). Actually, lets just cut to the chase... the ideal shape is "a bird". Every deviation from the basic bird bodyplan will probably lead to a heavier and less aerodynamic body which will need bigger wings to stay aloft and stronger muscles to take off.
The type of flying you intend to do also has a big impact on wing shape, and one which I'm not going to go into detail on here
So, in the absence of more information, lets consider one of the largest known flying birds, Pelagornis sandersi. Upper weight limit was about 40kg, conveniently about the weight of your guy. Wingspan was over 6m.
Remember this is a bird, so was optimised for life on the wing, not tottering around on the ground, holding tools, chatting with other beings, wearing clothes, etc etc. I believe this species was assumed to be a seabird, and those very long slender wings certainly look quite albatross-like, optimised for long efficient glides over great distances and extended times.
A much heavier bird (up to 70kg or so), Argentavis magnificens, had a similar wingspan, but much deeper wings (there's probably a better term in the aviation or ornithology worlds, but I'm not aware of it) to support that extra weight. Again, bird, optimised for flying (or at least soaring), none of the other people things you might be interested in.
The condor also in this picture weighs up to about 15kg and has a wingspan of over 3m. This should probably tell you that you can't just give your dude big fat condor-style wings and have him fit in a confined space... there's not too much chance you'll get away with wings under 4m, though it is tough to provide a more realistic minimum for you.
These should give you some idea of the sheer size needed, even if they don't give you a good idea of how radically different the body plan of a flyer is compared to a human (apparently a tree-dwelling ape who took up endurance running and burning things). Trying to combine the two bodyplans will be tricky, to say the least, but there are pages and threads and questions out there ad nauseam about anatomically plausible flying humans.
For a more unusual bodyplan, consider a pterosaur:
Frustratingly, no-one seems quite sure about how much those things actually weighed. Early estimates were ludicrously low. That Quetzalcoatlus sp. probably weighed at least as much as an adult human, with a 6m wingspan. Smaller pterosaurs obviously existed, but no-one knows how much they weighed either, but the possibility exists that with pterosaur style wings you might be able to give your guy a wingspan as low as 4m. Positively petite!
As a closing note, consider the attempts to make mere humans fly under their own power. Paragliders, outstretched wingspan of 8.4m. Hang-gliders 9m. Both are for adults, and both add 20-40kg, but they only scale down so far and only allow unpowered takeoff. Ornithopter... 32m, still needed an assisted takeoff. Pedal-powered propeller... 34m. Both of those needed olympic-class athletes to operate, which should give you some idea as to the athleticism and stamina your character needs to have in order to fly.