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