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