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