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