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