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