Any PHP experts ot there? Need help with functions

Im trying to build an Admin options menu which allows the user of a theme to select a colour scheme (which selects a specific stylesheet).

I have this code in the template:

<?php echo $options['color_scheme']; ?>

…which returns an item from the array ‘Red’, ‘Blue’, ‘Green’ or ‘Default’.

But this just inserts the word ‘Red’ ‘blue’ etc into the template, but I’d like it to indicate a stylesheet.

Any advice? Thanks!