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