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