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