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