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