I just used the gradiet tool, did a couple of radial blurs and then coloured it. The second layer is the same thing as the first except I used the Twirl filter after the radial blurs and then I coloured it and then blended the two layers together.
I don't know the exact settings on all the filters but you just gotta try new things and mess around with the filters and see what works. If something doesn't look good, I just undo and try something else. Not much more to it than that.