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