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