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