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