One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,15,18)(11,16,21,32)(12,14,25,30)(13,26,29,24)(17,27,33,28)(19,34,23,22)(20,35,36,39)(31,37,40,38)(2,5)(6,8)(9,11)(10,16)(12,23)(13,20)(14,22)(15,21)(17,31)(18,32)(19,25)(24,39)(26,35)(27,37)(28,38)(29,36)(30,34)(33,40) involution — undirected(9,12,14,18,15,25,30,10)(11,19,22,16,21,23,34,32)(13,24,27,33,29,26,28,17)(20,35,37,31,36,39,38,40)(9,13)(10,17)(11,20)(12,24)(14,27)(15,29)(16,31)(18,33)(19,35)(21,36)(22,37)(23,39)(25,26)(28,30)(32,40)(34,38) involution — undirected(1,3,4,7)(2,6,5,8)(11,21)(16,32)(19,23)(20,36)(22,34)(31,40)(35,39)(37,38)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.