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