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