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