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