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