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