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