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