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