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)(19,23)(20,22)(21,24)(25,26,30,34)(27,31,32,28)(29,37,39,33)(35,36,38,40)(11,15)(14,16)(17,18)(19,23)(20,22)(21,24)(25,27,30,32)(26,28,34,31)(29,35,39,38)(33,36,37,40)(9,10,12,13)(11,14,15,16)(17,18,20,22)(19,21,24,23)(25,27)(26,31)(28,34)(29,38)(30,32)(33,36)(35,39)(37,40)(1,2)(3,6)(4,5)(7,8)(9,10)(11,14)(12,13)(15,16)(17,18)(19,21)(20,22)(23,24)(25,28,30,31)(26,32,34,27)(29,36,39,40)(33,38,37,35)(1,3,4,7)(2,6,5,8)(9,11)(10,14)(12,15)(13,16)(17,19)(18,21)(20,24)(22,23)(25,29,30,39)(26,33,34,37)(27,35,32,38)(28,36,31,40)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.