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