One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,14)(8,18)(9,12)(10,13)(11,16)(15,20)(17,19)(21,22)(23,27)(24,29)(25,28)(26,30)(31,34)(32,36)(33,35) involution — undirected(1,2,4,3)(5,6)(7,14)(8,12)(9,18)(10,13)(11,17)(15,20)(16,19)(21,23)(22,27)(24,31)(25,33)(26,32)(28,35)(29,34)(30,36)(5,7,10,15)(6,11,13,19)(8,17,9,16)(12,20,18,14)(22,28)(24,25)(27,34)(29,30)(31,33)(35,36)(1,3,4,2)(7,15)(11,19)(14,20)(16,17)(21,24,26,25)(22,29,30,28)(23,31,32,33)(27,34,36,35)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.