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