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