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