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)(12,17,27,23)(13,18,29,28)(20,25,34,26)(21,30,35,31)(24,32,38,36)(33,39,37,40)(9,11,14,19,16,22,15,10)(12,23,25,34,27,17,26,20)(13,28,30,35,29,18,31,21)(24,37,39,32,38,33,40,36)(2,5)(6,8)(9,12,15,26,16,27,14,25)(10,17,11,20,19,23,22,34)(13,24,31,40,29,38,30,39)(18,32,21,33,28,36,35,37)(9,13,15,31,16,29,14,30)(10,18,11,21,19,28,22,35)(12,24,26,40,27,38,25,39)(17,32,20,33,23,36,34,37)(1,3,4,7)(2,6,5,8)(13,29)(18,28)(21,35)(24,38)(30,31)(32,36)(33,37)(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.