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