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