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