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