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