There are a lot of options for soap or detergent for UTV cleaning, including specially formulated cleansers for ORVs such as bike wash. The soap/detergent you use should be tough enough to tackle the grime and mud that comes with off-roading, but not corrosive enough to damage your machine’s body or mechanics. Mild washers are the name of the game. A degreaser may also be used in conjunction with the gentle cleanser, though not on plastic parts.
Some components of your SxS require their own kind of wash. If your vehicle has a polycarbonate windshield, don’t use a regular window cleaner, which can damage it. Instead, opt for hand soap, liquid dish soap, or some other analogously easy cleanser. Fabric cleaner, meanwhile, can freshen up your UTV’s seatbelts.