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