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