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