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