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