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