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)(11,16)(12,17)(13,19)(14,28)(15,20)(18,25)(21,35)(22,30)(23,32)(24,31)(26,33)(27,34)(29,36)(37,40)(38,39) involution — undirected(1,3,4,8)(2,5,6,7)(9,11,13,24,15,22,14,21)(10,16,19,31,20,30,28,35)(12,23,26,38,27,37,25,36)(17,32,33,39,34,40,18,29)(10,17)(11,21)(12,25)(13,14)(16,29)(18,19)(20,34)(22,24)(23,37)(26,27)(28,33)(30,39)(31,40)(32,35) involution — undirected(2,6)(5,7)(11,22)(16,30)(21,24)(23,37)(29,39)(31,35)(32,40)(36,38) involution — undirectedA 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.