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