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