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