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