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