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