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