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