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)(27,31)(28,30)(29,32)(33,35)(34,39)(36,38)(37,40)(1,2,5,6)(3,8,7,4)(10,13)(14,16)(26,28)(31,33)(32,36)(39,40)(1,3)(2,4)(5,7)(6,8)(9,10)(11,14)(12,13)(15,16)(17,19,21,18)(20,23,24,22)(25,27,30,35)(26,31,28,33)(29,37,38,34)(32,40,36,39)(1,2)(3,4)(5,6)(7,8)(9,11,12,15)(10,14,13,16)(17,20,21,24)(18,22,19,23)(25,28,30,26)(27,33,35,31)(29,32,38,36)(34,39,37,40)(1,4)(2,3)(5,8)(6,7)(25,29,30,38)(26,32,28,36)(27,34,35,37)(31,39,33,40)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.