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