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