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