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