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