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