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