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