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