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