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