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