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