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