You make mention of anti-gravity, but also talk about walkways on the sides of buildings. More than just anti-gravity (reducing the effects of gravity), this implies that your futuretech is actually directional gravity manipulation.
Anti-gravity alone would have a great effect on construction. Buildings of far taller sizes could be manufactured with greater ease - you would not need nearly as powerful cranes to lift building materials. If the anti-gravity technology can be built into the structure itself, you could potentially use lighter materials because the load of the whole building could be reduced. Either way, the end result is verticality - buildings would be very, very tall. (The manufacturing implications of gravity control technology is touched on, albeit briefly as it is not the focus of the story, in David Weber's Honorverse.)
Assuming the cost was cheap enough, anti-gravity would also drastically improve the capability of humans getting into orbit. As an alternative to tall terrestrial structures, you'd have the capability of building large structures in space. If the technology is truly directional gravity manipulation, you could provide those structures with internal artificial gravity, eliminating the micro-gravity related problems of long term space habitation. Anti-gravity without directional gravity manipulation would still reduce resupply concerns, making living in orbit more attractive.
Despite easing the engineering implications, I think the larger concern is the human factor. The human body uses a combination of what is effectively a gyroscope in the inner ear and visual stimulus to determine where you are and where you're going. Without really having directional gravity manipulation, there's no way for us to test it, but I suspect there would be issue with your proposed walkways - the ear, subject to gravity would be telling the brain one thing (down is towards my feet) while the eyes would be saying something different based on the horizon. In a space habitat, the horizon/orientation problem is mitigated because the environment is presumably small enough that your senses tell you you're inside at all times.
TLDR
Buildings would get taller and/or leave the planet completely, but the orientation would remain the same.