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