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