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)(27,37)(28,34)(29,39)(30,33)(31,35)(32,36)(38,40) involution — undirected(1,2)(3,7)(4,6)(5,8)(11,17)(15,21)(18,23)(22,24)(25,27,32,30)(26,33,36,37)(28,35,29,38)(31,34,40,39)(1,3)(2,5)(4,8)(6,7)(10,14)(15,21)(16,19)(22,24)(25,28,32,29)(26,34,36,39)(27,35,30,38)(31,33,40,37)(2,6)(5,7)(9,10)(11,15)(12,16)(13,14)(17,21)(18,22)(19,20)(23,24)(25,29,32,28)(26,34,36,39)(27,35,30,38)(31,37,40,33)(1,2)(3,5)(4,6)(7,8)(9,11)(10,15)(12,18)(13,17)(14,21)(16,22)(19,24)(20,23)(25,30,32,27)(26,33,36,37)(28,38,29,35)(31,34,40,39)(1,3)(2,7)(4,8)(5,6)(9,12,13,20)(10,16,14,19)(11,18,17,23)(15,22,21,24)(25,31,32,40)(26,35,36,38)(27,34,30,39)(28,33,29,37)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.