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