What is wrong with the graphics' appearance? Usually, manufacturers make these graphics to be treated somewhat like paint. You can clean them like you would clean paint with regular soap. If there is an "issue" with their appearance now, than that is another story.
I just use any rinseless or regular wash to clean them. If they need correction, I'd recommend Optimum's lotion polishes, slower speeds, and nothing firmer than a polishing pad.
For protection, I'd stay away from anything that resembles "wax", because over time it can get caught in the edges - no matter how careful you are. Use a WOWA sealant or Prima HydroMax.
Can you show us a pic of why they don't look great?