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