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