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