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