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