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