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