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