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