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