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