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)(11,14)(12,16)(13,15)(17,18,20,22)(19,21,23,24)(25,26)(27,28)(29,37)(30,31)(32,34)(33,40)(35,39)(36,38)(3,8)(5,7)(9,11,13,16)(10,14,15,12)(19,23)(21,24)(26,31)(27,34)(33,37)(35,38)(1,3)(2,5)(4,8)(6,7)(9,12)(10,11)(13,14)(15,16)(17,19,20,23)(18,21,22,24)(25,27)(26,32)(28,31)(29,38)(30,34)(33,36)(35,40)(37,39)(1,3)(2,5)(4,8)(6,7)(9,11)(10,12)(13,16)(14,15)(17,18)(19,21)(20,22)(23,24)(25,28,30,32)(26,27,31,34)(29,39,40,36)(33,38,37,35)(1,2)(3,5)(4,6)(7,8)(9,12)(10,11)(13,14)(15,16)(25,29,30,40)(26,33,31,37)(27,35,34,38)(28,36,32,39)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.