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