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