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