Alternatively, create a web app using ArcGIS Web AppBuilder, and configure the Select widget in the web app. The selection color of the Select widget can be changed. Refer to ArcGIS Web AppBuilder: Configure the Select widget for the steps to configure the widget in a web app.
The option to change the selection color is also available in ArcGIS Pro as an application setting that applies to ArcGIS Pro projects. Refer to ArcGIS Pro: Selection options for more information.