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