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