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