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