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