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