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