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