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