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