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