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