You can replicate the Services submenus' structure using the Mega menu settings, as shown on the screenshots below:

When you select "Mega Menu - Standard Layout" for the Sub menu display mode, the submenu will appear automatically. All you need to do is to select the columns' layout, e.g. 2 columns, 3 columns, 4 columns.

Please check this guide for more details on the Max Mega Menu plugin: Vamtam Beaver Themes: Guide to Max Mega Menu