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