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