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