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