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