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