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