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