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