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