Hey Tom

This is not possible with the plugin – however the plugin uses the WordPress queries so you should be able to modify them by using pre_get_posts

A quick look at doing this lead me to this:

http://wordpress.stackexchange.com/questions/14306/using-wp-query-is-it-possible-to-orderby-taxonomy

I believe the filters there *should* work with S&F but they are untested.

Thanks