I do not believe you can. The only values that are posted are the variable name and the value. In this particular case the varname is mylist and the value woud only ever be 1 or 2.
You have a couple of options. You could change the value to red and blue instead of the number or you could maybe use a combined value that uncluded both the number and the string.
I would think though that you always know that 1=red and 2=blue so it could easily be hard coded into the form processor.
Is there some reason you need both?