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