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