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