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