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