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