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