One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,15,19)(11,12,20,23)(13,17,14,18)(16,21,24,22)(25,26)(27,31)(28,33)(29,37)(30,34)(32,35)(36,40)(38,39)(2,5)(6,8)(9,11,15,20)(10,12,19,23)(13,16,14,24)(17,21,18,22)(25,27,30,36)(26,31,34,40)(28,35,29,38)(32,37,39,33)(3,7)(6,8)(9,12)(10,16)(11,18)(13,21)(14,22)(15,23)(17,20)(19,24)(25,27)(26,32)(28,35)(29,38)(30,36)(31,37)(33,40)(34,39) involution — undirected(1,3,4,7)(2,6,5,8)(9,13,15,14)(10,17,19,18)(11,16,20,24)(12,21,23,22)(25,28,30,29)(26,33,34,37)(27,35,36,38)(31,32,40,39)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.