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