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