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