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