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