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