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