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