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