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