How can I conceal interior camera wiring?
Like any wiring, you need to learn to put it in the walls/ceiling if you don't want to see it. 

This generally involves drilling holes in the wall/ceiling at minimum, and may also involve some larger holes and drywall repair. How difficult or easy it is depends on the specific construction details of the building and where you have access. 

It almost always involves some amount of surface repair and repainting.