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