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