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