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