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