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