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