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