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