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