I don't see any reason you can not use just plain contact paper.. the trick will be to get it to stick to the mat. Maybe you could use some spray adhesive on the back of the contact paper.. It's been three months since you asked this so you may have already done it. If you did, how did it turn out?
ps spray adhesive won't hurt your mat.. I've used it on mine forever.. it just puts some new "stick" on it. spray adhesive (at least Elmers brand) is meant to be permanent or temporary.. depending on how you apply it.