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)(23,31)(24,30)(25,29)(26,28)(27,33)(32,36)(34,35) involution — undirected(1,2,4,3)(5,6)(7,14)(8,12)(9,18)(10,13)(11,17)(15,20)(16,19)(21,23,25,33)(22,27,29,31)(24,32,26,34)(28,36,30,35)(5,7,10,15)(6,11,13,19)(8,17,9,16)(12,20,18,14)(22,28)(24,26)(27,35)(29,30)(31,36)(32,34)(1,3,4,2)(7,15)(11,19)(14,20)(16,17)(21,24,25,26)(22,28,29,30)(23,32,33,34)(27,36,31,35)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.