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