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