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