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