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