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