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