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