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