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