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)(11,18)(12,20)(13,15)(14,16)(17,22)(19,23)(21,24)(26,31)(27,33)(32,35)(34,39)(2,6)(3,7)(9,11,15,14)(10,16,13,18)(12,21,22,19)(17,24,20,23)(25,26,30,31)(27,29,33,38)(28,35,36,32)(34,40,39,37)(1,3)(2,4)(5,7)(6,8)(10,13)(16,18)(17,20)(23,24)(28,36)(32,35)(34,39)(37,40) involution — undirected(1,4)(2,3)(5,8)(6,7)(9,12)(10,17)(11,19)(13,20)(14,21)(15,22)(16,23)(18,24)(25,27)(26,29)(28,34)(30,33)(31,38)(32,37)(35,40)(36,39) involution — undirected(9,13,15,10)(11,16,14,18)(12,20,22,17)(19,23,21,24)(25,28,30,36)(26,32,31,35)(27,34,33,39)(29,37,38,40)(9,14,15,11)(10,16,13,18)(12,19,22,21)(17,24,20,23)(25,29)(26,33)(27,31)(28,37)(30,38)(32,39)(34,35)(36,40)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.