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