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