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