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)(25,26)(27,33)(28,30)(29,32)(31,35)(34,39)(36,37)(38,40)(1,3,4,8)(2,5,6,7)(9,11,13,12)(10,14,15,16)(17,18,21,20)(19,23,24,22)(26,28)(29,37)(31,33)(34,40)(9,12,13,11)(10,14,15,16)(17,19,21,24)(18,22,20,23)(25,27)(26,31)(28,33)(29,34)(30,35)(32,38)(36,39)(37,40)(1,2)(3,5)(4,6)(7,8)(17,18,21,20)(19,22,24,23)(25,28,30,26)(27,33,35,31)(29,36,37,32)(34,39,40,38)(1,3)(2,5)(4,8)(6,7)(9,10)(11,16)(12,14)(13,15)(17,20,21,18)(19,23,24,22)(25,29)(26,32)(27,34)(28,36)(30,37)(31,38)(33,39)(35,40)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.