This may vary from model to model but with my Map60CSx I can choose the colour of a Route or a Track in Mapsource but when downloaded to the GPS unit only the Tracks retain my chosen colour. Any Route downloaded will show on the unit only as a magenta highlighted line when "Navigated".
I've never used a Legend so I don't know what user options it offers in this regard, but it's probably a clue that in my model at least, I can open a Track and select or alter the colour in the unit itself. I cannot do this in the unit with Routes.
As an aid to visibility, some people load both a Track and a Route for the same ride and then alter the Track colour to say light green or cyan and set it to "Show on map" and then "Navigate" the Route. They then get a [cyan] Track line highlit by a magenta Route indicator. This also gives the added security of seeing if the path chosen by the GPS unit for the auto Route calculation (which won't always be the same as the path showing in Mapsource on your PC) diverts from the Track line, which the unit won't interfere with.
