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