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