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