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