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