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