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