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