Is the wearing of High Visibility garments "cool"? Probably not. But if your sole purpose in life is to be "cool" then I suggest staying away from motorcycles. Remember you're much less visible than other vehicles, and also far less protected. Anything you can do to maximise your visibility has to be a good thing. I also advise riding with your headlight on as well (in some countries this is law).
Unfortunately in the UK you're not allowed to have coloured headlights. In my view an orange-tinted headlight would be quite a good thing as it would enable you to stand out from the rest of the traffic. When riding at night you need to bear in mind that in a driver's rear-view mirror (if they bother to use this at all) your headlight will blend in with those of other vehicles; in fact you may even be mistaken for a car with only one working headlight - there are quite a few of these around!
As previously mentioned, I combined my "waterproof" requirement with my "brightly-coloured fluorescent" requirement by wearing a Hi-Viz waterproof padded jacket which I bought from, would you believe, a welding equipment shop. Well the prices were cheap! It also has a hood which can be folded into the collar when not in use. I have since purchased another; the first one sustained a torn sleeve. Riding home in a downpour, I failed to notice a metal manhole cover in the centre of the road, in a curve. Very thoughtful of the road-designers, that was. Well, the front wheel slipped out and I went down. The torn sleeve was the only damage. At least it protected my leather jacket! The old coat is now being worn around the farm.
Nowadays high-visibility apparel is available from various outlets, in various styles and colours, ranging from vests, long-sleeved vests, through to coats and jackets. Or instead of a fluorescent jacket, you could go for a Sam Browne type reflective belt. I tend to wear mine in summer when it's a bit too warm for a padded jacket.
In France, the government is attempting to make the wearing of high visibility garments compulsory. Unfortunately their recommendations for safety clothing stops there - under the terms of this proposed law you can ride a motorcycle naked, as long as you're wearing a high visibility vest and a helmet.
For further reading, have a look at the FFMC.