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