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)(10,14)(11,23)(12,15)(13,19)(16,26)(18,34)(20,31)(21,32)(22,29)(24,28)(25,30)(27,35)(33,36)(37,38)(3,5,6,4)(7,9)(8,13)(10,18)(11,24)(12,20)(14,27)(15,28)(16,31)(17,23)(19,26)(21,37)(22,36)(25,35)(29,38)(30,33)(32,34)(7,10,12,22)(8,14,15,29)(9,18,20,36)(11,25,26,21)(13,27,28,38)(16,32,23,30)(17,33,31,34)(19,37,24,35)(8,15)(13,28)(14,29)(16,23)(17,31)(27,38)(30,32)(33,34) 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.