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