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)(11,16)(12,14)(13,21)(15,17)(18,22)(19,23)(20,24)(25,26,31,28)(27,35,36,32)(29,33,40,38)(30,39,37,34)(1,2)(3,6)(4,7)(5,8)(9,11,15,12)(10,16,17,14)(13,20,22,19)(18,23,21,24)(25,27)(26,32)(28,35)(29,30)(31,36)(33,34)(37,40)(38,39)(10,17)(11,12)(13,22)(23,24)(27,36)(29,40)(32,35)(33,38) involution — undirected(1,3,5,4)(2,6,8,7)(9,12,15,11)(10,14,17,16)(13,20,22,19)(18,23,21,24)(25,28,31,26)(27,35,36,32)(29,38,40,33)(30,39,37,34)(9,13)(10,18)(11,19)(12,20)(14,23)(15,22)(16,24)(17,21)(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)(9,14)(10,11)(12,17)(13,23)(15,16)(18,19)(20,21)(22,24)(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.