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