Dear Praveen,
You can use CSS styling for this.
Dough if you have to replace the full loading indicator there are some hacks shown in this lib.
https://github.com/mendix/MobileFeatures/blob/master/src/MobileFeatures/widget/plugins/spinner.js
when taking this approach, be care full, as you will overwrite part of the API it could give trouble in the future.
Cheers,
Andries