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