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