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