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