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