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