Another good place to look for by laws is in the book titled Robert's Rules of Order. It has almost all of the information any organization could need to get at the very least started on the by law trail.
I bet there are lots of folks who will share a copy of their by-laws with you. There is no single set of PTO by-laws. Individual groups set their own depending on your goals and concerns.
If you look in the section of this Board called "PTO Websites," (and look in the string "list your Website") you'll find one school that has its by-laws right online. That's one place to start.
