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