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