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