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