i perfer the silver color of lead. that way people know that ist lead tape. if you put electrical tape over it people will ask what happend to your racquet
They'll notice if they're looking to buy your racquet when you try to sell it on e b a y sometime down the road.
I wouldn't recommend covering the lead tape. I know it'd cosmetically "improve the look", but the idea with lead tape is to know you have it on there, and know how much you put on, so that if you ever want to change the setup or sell the racquet, there are no mysteries.
You could always spray paint the tape BEFORE you put it on your racket, or try a couple passes with a fresh Sharpie marker. It'll at least make it the tape a little less visible.