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