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