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