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