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