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