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