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