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