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