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