By default, Landscape displays all layers as green polygons, lines, or points. If you'd like different layer types to have different symbology (appearance) by default, you can do so via the settings menu. You must have administrator privileges in order to change the settings, and they will be applied across the whole organization, not just in your account.
Go to Settings in the upper right corner of the home page:
Go to 'Map Layers'
Under 'Built-in Layer Styles' you can click on any of the symbols to change them in the way that you would any other map layer.
Note: Changing the layer appearance in this way will not alter layers in maps you have already changed. Only map layers which have not been altered will be updated.