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