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