Can I color non transplanted hair (sides) after hair transplant ?

you should check with the hair restoration surgeon who performed your procedure for his or her recommendations. it is typically safe to color the hair around the donor area that was not harvested at the 2 week period, by then all the scabbing should be gone and the area healed.

It depends a little on if you have FUT or FUE.  If the hairs you want to color are NO WHERE CLOSE to the incision or donor sites, you could probably color after a week.  By 2 weeks, you can do whatever you want.  Always check with your surgeon though.  Good luck!