Just try not to feel too special over it.. having Synesthesia (or pretending to have it) is a good way to put urself on the ego train
What i'm saying is.. good way to get a musical superiority complex/feeling of magical purpose LOL.. unless it helps you make music, ur just seeing visuals which is kind of retarded. I think if you are seeing musical colours, then you should go research what's happening, try develop/maybe it can be used for something.