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