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