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