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