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