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