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