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