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