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