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