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