Removing spray paint from a vehicle can be a race against time. The faster you can get to it, the less time it can set and the easier it will be to remove.
First, you are going to want to try something simple. Goo-gone or acetone can work well. Just dab some on a microfiber and on a small area where the spray paint is thinner see if it removes any at all.
If that does not work, you can try and use a clay bar. Keep in mind you will need a lot of lubricant as the paint will gum up the clay and it will need to be tossed after.
Next, you can try polishing it. Grab a microfiber pad and a compound like Menzerna Heavy Cut Compound 400. Use a little bit faster arm movement as you are not trying to perfect the paint at this point you are just trying to remove the spray paint. Clean it out very often and it will need to be tossed after.
If that does NOT work, you will have to resort to wet sanding. This can be hard as spray paint gets everywhere right? So, it can be difficult to sand in all those areas, and then even more difficult to then remove those sanding marks. If you get to this point you really need to asses the options and if it makes sense to try to improve it, or just get insurance involved for a re-paint.