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