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