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