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