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