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