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