c.CustomProvider(defaultProvider => new ODataSwaggerProvider(defaultProvider, c));

// Let's say you map a custom OData route that doesn't follow the typical conventions
var customODataRoute = config.MapODataServiceRoute("CustomODataRoute", ODataRoutePrefix, GetModel(), batchHandler: null, pathHandler: new DefaultODataPathHandler(), routingConventions: myCustomConventions);

// Then describe your route to Swashbuckle.OData so that it will appear in the Swagger UI
config.AddCustomSwaggerRoute(customODataRoute, "/Customers({Id})/Orders")
    .Operation(HttpMethod.Post)
    // The name of the parameter as it appears in the path
    .PathParameter<int>("Id")
    // The name of the parameter as it appears in the controller action
    .BodyParameter<Order>("order");

[ResponseType(typeof(Order))]
public async Task<IHttpActionResult> Post([FromODataUri] int customerId, Order order)
{
  ...
}

httpConfiguration
    .EnableSwagger(c =>
    {
        // Use "SingleApiVersion" to describe a single version API. Swagger 2.0 includes an "Info" object to
        // hold additional metadata for an API. Version and title are required but you can also provide
        // additional fields by chaining methods off SingleApiVersion.
        //
        c.SingleApiVersion("v1", "A title for your API");

        // Wrap the default SwaggerGenerator with additional behavior (e.g. caching) or provide an
        // alternative implementation for ISwaggerProvider with the CustomProvider option.
        //
        c.CustomProvider(defaultProvider => new ODataSwaggerProvider(defaultProvider, c, () => httpConfiguration));
    })
    .EnableSwaggerUi();