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