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