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