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