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