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