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