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