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