HI Katy-
I found a few sites that you might be interested in. Check these out....hopefully one of them will have the (free) pattern that you are looking for!
http://www.birdcrossstitch.com/soakers/pattern/
http://tierra-verde.8m.com/soaker.html
http://diaperpages.com/soaker.php
http://www.bevscountrycottage.com/baby.html