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