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