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