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