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