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