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