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