A spot we really liked was just before the kiddie area on the left hand side of the walkway, there are a few sandy areas bordering the lazy river with chairs, they are smaller and fit only one group. Its shady and very close to the kiddie play area, along with being really accessable to the walkways. I think that there was about four or five chairs there.
There are also nice areas of shade along the wave pool, but when we went our daughter was two and a half and the waves are pretty big, I felt safer in the area we chose, there was a rope boundary on three sides. She was pretty content playing in the sand while she was warming up from playing on the slides. And I felt more at ease knowing that our spot provided some level of containment.
I imagine that there are other spots equally as nice as the one we found and possibly closer to some water. But as was mentioned above you need to get there early to stake your claim.
Have fun! Typhoon Lagoon is my favorite!