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