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