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