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