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