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