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