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