In my experience, these pipes are conventional 'fuel' type connections (i'm sure someone else here knows the proper name for them). Push the coloured section on the side, or the two coloured sections on opposite sides and it should release.
Sometimes, if it's a little stiff, push the connection down whilst pressing the coloured sections and it makes releasing it a bit easier. There are special pliers for this purpose but accessibility is not always ideal. And usually can be done by hand anyway.