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