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