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