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