One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,6)(7,8,12,16)(9,17,20,30)(10,14,21,28)(11,23,25,15)(13,24,27,19)(18,31,32,38)(22,35,34,29)(26,36,37,33)(3,4,5,6)(7,9,12,20)(8,13,16,27)(10,18,21,32)(11,24,25,19)(14,26,28,37)(15,30,23,17)(22,36,34,33)(29,38,35,31)(7,10)(8,14)(9,18)(11,22)(12,21)(13,26)(15,29)(16,28)(17,31)(19,33)(20,32)(23,35)(24,36)(25,34)(27,37)(30,38) involution — undirected(10,21)(14,28)(18,32)(22,34)(26,37)(29,35)(31,38)(33,36) involution — undirectedA 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.