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