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