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