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