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