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