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