Your page load time will depend on many different factors. Most often it’s the size of the images being served on the site.
Also, since it is a one-page theme and includes a lot of content it can usually be heavier than most pages.
Try using a tool like https://developers.google.com/speed/pagespeed/insights/ to locate the image files which are large so you can optimize them for the web (reduce them in size and resolution).
You can also use a caching plugin like W3C Total Cache https://en-ca.wordpress.org/plugins/w3-total-cache/