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