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