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