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