As the graphic is a vertical one you could, 4 example: cut every segment in a .gif or .png image. And (with perl) use a table to fix them in every cell of the same column. Those segments might be transparent with only their particular white background. Later, every table´s cell would have a different class name that would address to certain characteristics in it's background color. But since the picture's background color is always white, and only the solid is transparent. By changing the cell's background, programatically, you could change the segment's color.
Your script should change the CSS class color, and by this, you might change that segment's color. Or you might need to change several classes' colors, and that is the same effect with a lot of table cells with that same color.