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)(11,15)(12,17)(13,22)(14,18)(16,19)(20,24)(21,23)(26,31)(27,34)(28,35)(30,37)(32,39)(36,40)(1,3,4,8)(2,5,6,7)(9,11)(10,15)(12,21)(13,19)(14,20)(16,22)(17,23)(18,24)(25,26,29,31)(27,32,28,36)(30,33,37,38)(34,40,35,39)(9,11)(10,16)(12,19)(13,21)(14,20)(15,22)(17,24)(18,23)(25,27,29,28)(26,32,31,36)(30,35,37,34)(33,39,38,40)(9,12,14,13)(10,17,18,22)(11,19,20,21)(15,16,24,23)(25,28,29,27)(26,32,31,36)(30,34,37,35)(33,39,38,40)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.