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