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