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