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