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