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