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