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