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