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