What color of coolant for 2002?

I am helping out someone who wants to winterize their car, I noticed the coolant levels were down so could not tell which color is in it. This is the first time working on a Volvo, so not familiar but have read that there are several colors available for the coolant and to not mix them.

I am thinking to flush out the old coolant, so does it matter which color that goes back in?