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