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