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