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