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