Hola Montse
Es necesario incluir un poco de JavaScript donde se muestra el mapa para actualizar los opciones requeridos.
Copia el siguiente al sección custom JS del Loop Output Editor (ten cuidado editar el map id, "map-1" en este ejemplo):
jQuery( document ).ready( function( $ ) {
$( document ).on( 'js_event_wpv_addon_maps_init_map_completed', function( event ) {
var map = WPViews.view_addon_maps.get_map('map-1');
var styles = [
{
"elementType": "geometry",
"stylers": [
{
"color": "#f5f5f5"
}
]
},
{
"elementType": "labels.icon",
"stylers": [
{
"visibility": "off"
}
]
},
{
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#616161"
}
]
},
{
"elementType": "labels.text.stroke",
"stylers": [
{
"color": "#f5f5f5"
}
]
},
{
"featureType": "administrative.land_parcel",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#bdbdbd"
}
]
},
{
"featureType": "poi",
"elementType": "geometry",
"stylers": [
{
"color": "#eeeeee"
}
]
},
{
"featureType": "poi",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#757575"
}
]
},
{
"featureType": "poi.park",
"elementType": "geometry",
"stylers": [
{
"color": "#e5e5e5"
}
]
},
{
"featureType": "poi.park",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#9e9e9e"
}
]
},
{
"featureType": "road",
"elementType": "geometry",
"stylers": [
{
"color": "#ffffff"
}
]
},
{
"featureType": "road.arterial",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#757575"
}
]
},
{
"featureType": "road.highway",
"elementType": "geometry",
"stylers": [
{
"color": "#dadada"
}
]
},
{
"featureType": "road.highway",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#616161"
}
]
},
{
"featureType": "road.local",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#9e9e9e"
}
]
},
{
"featureType": "transit.line",
"elementType": "geometry",
"stylers": [
{
"color": "#e5e5e5"
}
]
},
{
"featureType": "transit.station",
"elementType": "geometry",
"stylers": [
{
"color": "#eeeeee"
}
]
},
{
"featureType": "water",
"elementType": "geometry",
"stylers": [
{
"color": "#c9c9c9"
}
]
},
{
"featureType": "water",
"elementType": "labels.text.fill",
"stylers": [
{
"color": "#9e9e9e"
}
]
}
];
map.setOptions({styles: styles});
});
});
Nota que el var styles proviene de este wizard para generar estilos: hidden link
Yo elegí la tema plata. Si quieres puedes hacer cualquier modificación y copiar el JSON resultante al código arriba.