Example of S3TileMapServiceLayer class using the ArcGIS Javascript API, which gets the map service definition from an ArcGIS Server endpoint, and accesses the tiles from S3

S3TiledMapServiceLayerHybrid.js

dojo.require("esri.map");
dojo.require("esri.layers.agstiled");
dojo.require("dojo/string");

var map;

function init() {

    dojo.declare("S3TiledMapServiceLayer", esri.layers.ArcGISTiledMapServiceLayer, {

        constructor: function(mapServiceUrl, externalS3TileCacheUrl) {
            this._s3TileUrl = externalS3TileCacheUrl;
            dojo.safeMixin(this, mapServiceUrl);
        },  // constructor        
    
        getTileUrl: function(level, row, col) {
            return this._s3TileUrl
                    + "/L" + dojo.string.pad(level.toString(), 2, '0')
                    + "/R" + dojo.string.pad(row.toString(16), 8, '0')
                    + "/C" + dojo.string.pad(col.toString(16), 8, '0')
                    + ".png";
        } // getTileUrl
    
    });

    var initExtent = new esri.geometry.Extent({ "xmin": 152.260192894019, "ymin": -27.6147957518947, "xmax": 153.686679767014, "ymax": -26.9985153513847, "spatialReference": { "wkid": 4283} });
    map = new esri.Map("map",{extent:initExtent});
    
    var tiledLayer = new S3TiledMapServiceLayer("http://<SERVER_NAME>/ArcGIS/rest/services/<MAP_SERVICE_NAME>/MapServer", "https://<S3_BUCKET.s3.amazonaws.com/_alllayers");
    map.addLayer(tiledLayer);

    dojo.connect(map, 'onLoad', function(theMap) {
        //resize the map when the browser resizes
        dojo.connect(window, 'resize', map,map.resize);
    });
}

dojo.addOnLoad(init);