You Do Need power plug adapter while traveling from Senegal to Cocos (Keeling) Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Cocos (Keeling) Islands is I and in Senegal are C, D, E and K. This is how they look like.

Senegal

In Senegal, outlets of type C, D, E and K are in use.

Type C

Type D

Type E

Type K

Cocos (Keeling) Islands

In Cocos (Keeling) Islands, outlets of type I are in use.

Type I