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