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