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