One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(5,6)(7,15)(8,18)(9,20)(10,12)(11,17)(13,19)(14,16)(21,22)(23,27)(24,32)(25,34)(26,29)(28,33)(30,36)(31,35) involution — undirected(5,7,9,17,10,8,16,19)(6,11,14,15,12,13,20,18)(21,23,26,31)(22,27,29,35)(24,33,30,25)(28,36,34,32)(1,2,3,4)(6,12)(11,13)(14,20)(15,18)(21,24,25,23,26,30,33,31)(22,27,28,32,29,35,34,36)(5,8,9,19,10,7,16,17)(6,13,14,18,12,11,20,15)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.