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