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