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