One way to do it is to have an external file with all your svg data that you append to the dom afterwards. Wherever you want to use a svg, just reference the appended svgs:

    <svg><use xlink:href='#svg-id'></use></svg>

Here's a quick example I threw together: http://syd.jjcm.org/svgCacheTest

If you click on the folder icon you can see it being changed by the css.