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