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