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