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