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