Here's a previous thread with some info
Aftermarket Cruise Control?
and here's another
Cruise Control for 2012 S Model Cars
TL;DR it looks like you can get a new OEM steering wheel (might not work with the S) or go with one of a few aftermarket companies. Expect to pay ~$3-400. Had an aftermarket kit put on my jeep in 2005 and it was around $400 installed and doesn't work anymore.
I researched this too because I initially bought a SE w/o cruise and didn't realize it 'till I drove off the lot. Good thing they have a 7 day return policy!