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