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