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