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