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