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