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