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)(12,20)(13,16)(14,18)(15,21)(19,22)(23,24)(25,26)(27,32)(28,29)(30,40)(31,34)(33,38)(35,39)(36,37)(2,5)(6,7)(9,10,13,16)(11,14,18,17)(12,15,21,20)(19,22,24,23)(25,27,31,30)(26,32,34,40)(28,35,38,37)(29,39,33,36)(1,2)(3,6)(4,5)(7,8)(11,18)(14,17)(19,24)(22,23)(25,28)(26,33)(27,35)(29,34)(30,37)(31,38)(32,36)(39,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11,13,18)(10,14,16,17)(12,19,21,24)(15,22,20,23)(25,29,31,33)(26,28,34,38)(27,36,30,39)(32,37,40,35)(1,3,4,8)(2,6,5,7)(9,10)(11,14)(12,15)(13,16)(17,18)(19,22)(20,21)(23,24)(25,30,31,27)(26,32,34,40)(28,37,38,35)(29,39,33,36)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)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.