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