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