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