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