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