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