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