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