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