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