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)(11,17)(12,16)(13,15)(14,18)(19,23)(20,22)(21,24)(25,26)(27,35)(28,34)(29,33)(30,32)(31,36)(37,39)(38,40) involution — undirected(1,3,5,2)(4,7,8,6)(9,11,13,18)(10,14,15,17)(12,19,20,24)(16,21,22,23)(25,27,30,36)(26,31,32,35)(28,38,29,37)(33,40,34,39)(1,4)(2,6)(3,7)(5,8)(9,10)(11,14)(12,16)(13,15)(17,18)(19,21)(20,22)(23,24)(26,32)(27,36)(33,34)(37,38) involution — undirected(2,3)(4,8)(10,15)(14,17)(16,22)(21,23)(25,28,30,29)(26,33,32,34)(27,37,36,38)(31,39,35,40)(2,3)(6,7)(11,18)(14,17)(19,24)(21,23)(25,29,30,28)(26,34,32,33)(27,37,36,38)(31,39,35,40)(9,12,13,20)(10,16,15,22)(11,19,18,24)(14,21,17,23)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.