Hmmm. It's faded and chalky from oxidation and UV damage.
You can sort of hide the effect (and bring back a darker color) by using a product that will wet the chalkiness. 303 Aerospace works pretty well, but may require reapplication pretty often. Other plastic/vinyl restorers/conditioners may work as well (no comment on the ecological implications, though.)
There may be some solvents that will break down the oxidation, and get you back to base material. Might try small areas with a small dryish brush and various solvents, like acetone, MEK, toluene, or mineral spirits.
Don't know what kind of paint you'd use, but surface prep would be pretty critical, I would think, which means that you'd already be most of the way to a surface restoration.