I would guess the visible light image is not nearly so colorful.
That’s what Ted Turner said.
Yes, “representative colors” were used. They may have combined visible with non-visible images from infrared, ultraviolet and/or X rays where they had to represent a non-visible spectrum in a color we can see. It could also be an image where they isolated emission signatures from different elements and showed them in different colors. Unfortunately they don’t usually give details like that. I think it would be interesting to many of us.
Trying to find out, but, I think it may be real color. Planetaries are strange beasts, and, if there is a large magnetic field, it can do some strange things with color.
Even if it is ‘Hubble Pallet’ color, they look pretty.