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