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