We do have a liquid formulation of cypermethrin called Cyper TC that should fit your needs very well. Since this is an emulsifiable concentrate, it may cause staining to old vinyl siding so you may want to test a small area if this is an issue for you. If staining is a problem then you could use water based, non staining Talstar P as an alternative. Both products should work just fine in a hose end sprayer.
***Note: We do NOT recommend spraying swing sets or swings of any sort with any type of insecticides. Spraying around the perimeter of the play set area should be sufficient.****