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